Quantum Computing
Quantum Computing news — Thursday 01 October 2026
150 stories from 3 sources, every one in English. Each links to its publisher.
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Unitary Foundation Launches Its 2026 Quantum Open Source Software Survey
Quantum Computing Report
The Unitary Foundation has launched its 2026 Quantum Open Source Software (QOSS) survey, an annual initiative designed to collect information on the quantum open-source software community. The survey includes questions on demographics…
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Quanome CEO to Back Quantum Strategy with Up to $15 Million in Non-Dilutive Growth Capital
The Quantum Insider
Insider Brief Quanome Technologies entered into a revolving loan agreement with CEO and Chairman Yang Li for up to $15 million in non-dilutive growth capital. Approved advances will carry 6% annual interest and may be used for working…
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Quantum Renaissance to Convene Global Quantum Leaders in Florence in April 2027
The Quantum Insider
Insider Brief Quantum Renaissance will bring together leaders from research, industry, government and finance at Palazzo Vecchio in Florence on April 1-2, 2027, to examine quantum technology’s development and wider implications. Organized…
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D-Wave Launches Gate-Model Simulator Beta Program Featuring 21-Qubit Dual-Rail Erasure Emulation
Quantum Computing Report
D-Wave has launched a beta program for its gate-model quantum computing simulator, accessible via its Leap quantum cloud service. The simulator supports up to 21 qubits with both ideal and hardware emulation modes and models D-Wave's…
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NATO Releases Official Quantum Technology Roadmap Establishing Operational Timelines and Standardization Frameworks
Quantum Computing Report
NATO has released its Quantum Technology Roadmap, effective July 2026, to implement its 2023 Quantum Technology Strategy. The roadmap outlines Lines of Effort in quantum computing, sensing, and communications, with target milestones to…
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Classiq Launches Fault Tolerance Engine for Hardware-Aware Quantum Application Synthesis
Quantum Computing Report
Classiq has launched its Fault Tolerance Engine, a new tool integrated into the Classiq SDK. This engine translates high-level quantum circuits into detailed, hardware-aware execution plans for fault-tolerant quantum processors…
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Pasqal Appoints Florence Lao as Chief Legal Officer
The Quantum Insider
Insider Brief Pasqal appointed Florence Lao as Chief Legal Officer to oversee the company’s global legal strategy as it expands as a publicly traded quantum computing company. Lao will lead work across corporate governance, securities law…
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Researchers Demonstrate Building Blocks for Zinc Oxide Spin Qubits
The Quantum Insider
Insider Brief Researchers demonstrated charge sensing, high-frequency reflectometry and a few-electron double quantum dot in zinc oxide, establishing tools for developing semiconductor spin qubits. An integrated sensor and radio-frequency…
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D-Wave Launches Gate-Model Quantum Simulator Beta
The Quantum Insider
Insider Brief D-Wave launched a beta program for its gate-model quantum computing simulator, giving selected customers early access to error-aware programming tools. The simulator is based on D-Wave ’s dual-rail superconducting gate-model…
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California Signs Fusion Legislation and Announces $30 Million Quantum Investment
The Quantum Insider
Insider Brief California Governor Gavin Newsom signed legislation establishing a strategic framework for fusion energy and announced a new $30 million investment for quantum and deep-space research. The new fusion legislation calls for a…
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Choi Co-Leads Research on Quantum Intelligent Sensor Networks
The Quantum Insider
Insider Brief Stony Brook University and the University of Hawaiʻi at Mānoa researchers are collaborating on a three-year NSF -funded project to develop quantum intelligent sensor networks. The project will study how distributed quantum…
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Diraq to Establish Quantum R＆D Lab in New Mexico
The Quantum Insider
Insider Brief Diraq plans to establish a quantum research and development laboratory at Roadrunner Quantum Lab in Albuquerque, New Mexico, with operations expected to begin by the end of 2026. The facility will include cryogenic equipment…
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Scientists Find Structural Guide to Unusual Magnetism in Quantum Materials
The Quantum Insider
Insider Brief Researchers in Japan found that a crystal’s structural dimensions classified magnetic states more consistently than electron concentration across a family of complex alloys. The compounds exhibited distinct magnetic states at…
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Alice ＆ Bob Demonstrates New Approach to Stabilizing Cat With DC Voltage Bias
The Quantum Insider
Insider Brief Alice & Bob and ENS Lyon demonstrated a voltage-driven approach to stabilizing cat qubits that could enable more compact quantum hardware with lower heat generation. The device achieved a two-photon exchange rate of 3 MHz…
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Alice ＆ Bob and ENS Lyon Demonstrate DC-Biased SQUID Architecture for Multi-Photon Cat Qubit Dissipation
Quantum Computing Report
Alice & Bob and ENS Lyon have demonstrated a DC-biased SQUID architecture for stabilizing cat qubits, replacing traditional microwave pumps with a microvolt-scale DC voltage. This method eliminates unwanted Kerr nonlinearities and provides…
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Governor Newsom Signs Fusion Legislation and Allocates State Capital to Advance California Quantum Infrastructure
Quantum Computing Report
California Governor Gavin Newsom has signed legislation and allocated $30 million for quantum and deep-space research to advance the state's technology infrastructure. This initiative, known as Quantum California, supports university…
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Classical simulation of coherent crosstalk in surface codes
arXiv quant-ph
arXiv:2609.40279v1 Announce Type: new Abstract: We give a polynomial-time classical algorithm which samples from the syndrome distribution of a surface code state corrupted by coherent nearest-neighbor $ZZ$ crosstalk. Our algorithm…
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Conditioning-Free Non-Uniform Quantum Fourier and Chebyshev Transforms
arXiv quant-ph
arXiv:2609.40277v1 Announce Type: new Abstract: We present an efficient quantum algorithm for the non-uniform Chebyshev transform. It is defined as the projection of a function onto Chebyshev polynomials sampled at given nodes that are…
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Quantum Time-Lock Puzzles in the Quantum Random Oracle Model
arXiv quant-ph
arXiv:2609.38894v1 Announce Type: new Abstract: A time-lock puzzle allows a sender to hide a message in a puzzle such that recovering the message requires substantially more sequential computation than the time required to generate the…
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Logarithmic-Depth Fermion Sampling: Anticoncentration and Average-Case Hardness
arXiv quant-ph
arXiv:2609.40100v1 Announce Type: new Abstract: Sampling problems give some of the clearest conditional separations between quantum and classical computation. In Fermion Sampling, passive linear optics acts on a non-Gaussian magic input…
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Fault-Tolerant Quantum Computation with Adversarial Errors
arXiv quant-ph
arXiv:2608.16857v2 Announce Type: replace Abstract: We prove a fault-tolerance theorem for quantum computation against adversarial noise. For every quantum circuit on $\bar{N}$ logical qudits of depth $\bar{T}$, we construct a…
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Natural Barriers to Quantum Extraction: On the Post-Quantum (In)security of (O)EKE and Masny-Rindal OT
arXiv quant-ph
arXiv:2609.39844v1 Announce Type: new Abstract: Encrypted key exchange (EKE), introduced by Bellovin and Merritt (IEEE S\&P 1992), and Masny-Rindal OT, introduced by Masny and Rindal (ACM CCS 2019), are highly-efficient methods for…
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Joint measurability of coplanar POVMs
arXiv quant-ph
arXiv:2609.38836v1 Announce Type: new Abstract: An unbiased qubit positive operator-valued measure (POVM) can be uniquely expressed in terms of the Bloch vector. We prove that for POVMs with coplanar Bloch vectors, they are jointly…
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A Memory-Magic Exchange Law in Streaming Clifford+T Compilation
arXiv quant-ph
arXiv:2609.37368v2 Announce Type: replace Abstract: A phase that reaches a fault-tolerant processor in additive pieces can be remembered until the last piece arrives, or executed on arrival: the first option costs classical memory carried…
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Pure gapped ground states of spin chains are short-range entangled
arXiv quant-ph
arXiv:2511.14699v3 Announce Type: replace-cross Abstract: We consider spin chains with a finite range Hamiltonian. For reasons of simplicity, the chain is taken to be infinitely long. A ground state is said to be a unique gapped ground…
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Smart Machine Learning for Solving the Full Electron-Nuclear Schr\"odinger Equation with a Quantum-Chemically Inspired Wavefunction Ansatz
arXiv quant-ph
arXiv:2609.40112v1 Announce Type: cross Abstract: Directly solving the full electron-nuclear Schr\"odinger equation remains one of the grand challenges in quantum mechanics. Here, we propose a quantum-chemically motivated orbital-based…
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Quantum State Readout via Overlap-Based Feature Extraction
arXiv quant-ph
arXiv:2505.08613v2 Announce Type: replace Abstract: In this study, a method for quantum state readout and feature extraction is developed using quantum-overlap-based fitting of function expansions. The approach involves the quantum…
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Interferometric Readout of Momentum-Space Topology in a Programmable Dissipative Photonic Circuit
arXiv quant-ph
arXiv:2609.38352v1 Announce Type: new Abstract: Topology under non-Hermitian dynamics is encoded in the phase of the bulk evolution, yet strong dissipation suppresses the amplitudes carrying it. We resolve this using a programmable…
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Copy-scarce learning of ground states
arXiv quant-ph
arXiv:2609.38513v1 Announce Type: new Abstract: Probing multiple properties of ground states is central to understanding quantum matter, yet conventional readout can be prohibitively costly because it consumes many independently prepared…
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Fixed-Point Bifurcations and Path-Information Bounds in Nonlinear Exceptional-Point Sensing
arXiv quant-ph
arXiv:2609.39046v1 Announce Type: new Abstract: Nonlinear exceptional points (NEPs) were proposed to circumvent the noise--responsivity cancellation that limits linear exceptional-point sensors. At an NEP, the stationary frequency response…
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Exponential separation in sensing continuous signals via squeezing
arXiv quant-ph
arXiv:2609.38678v1 Announce Type: new Abstract: Quantum sensing traditionally focuses on using quantum resources such as squeezing and entanglement to improve precision for sensing fixed signals. However, in many applications such as…
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Universal magic state concentration
arXiv quant-ph
arXiv:2608.13376v2 Announce Type: replace Abstract: Magic plays a dual role in quantum computation: it promotes stabilizer dynamics from efficient classical simulability to computational universality, but also challenges fault-tolerant…
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Fast mixing of all-to-all quantum systems at high temperatures
arXiv quant-ph
arXiv:2606.26090v2 Announce Type: replace Abstract: It is shown that arbitrary quantum $k$-local Hamiltonians with bounded strength interactions admit a quantum Gibbs sampler [CKG23] with a system-size independent spectral gap, at…
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Optimal learning of covariant quantum states and channels
arXiv quant-ph
arXiv:2609.39280v1 Announce Type: new Abstract: We give collective tomography protocols for quantum states and channels with known symmetries, using random purification and dilation to reduce learning to pure-state estimation. For states…
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Landscape Compression in Constrained QAOA Tracks Feasibility Loss on IBM Heron Hardware
arXiv quant-ph
arXiv:2604.19426v2 Announce Type: replace Abstract: We study how hardware noise changes the p=1 Quantum Approximate Optimization Algorithm (QAOA) landscape for cardinality-constrained portfolio problems on ibm_fez (IBM Heron r2): seven…
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Optimal Scaling of Unitary Design Formation in $U(1)$-Symmetric Random Circuits: A Bottleneck Slower than Charge Transport
arXiv quant-ph
arXiv:2609.39458v1 Announce Type: new Abstract: Understanding randomness formation under conservation laws is important both for characterizing chaotic phenomena in isolated quantum systems and for symmetry-constrained quantum information…
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On the Computational Power of Geometrically Local QAC circuits
arXiv quant-ph
arXiv:2604.07178v2 Announce Type: replace Abstract: The computational power of $\mathsf{QAC}$, which are constant-depth quantum circuit families consisting of arbitrary single-qubit unitaries and n-qubit generalized Toffoli gates, has…
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Geometric Characterization and Feasible Region Analysis of Bipartite Qutrit Bound Entanglement
arXiv quant-ph
arXiv:2609.39141v1 Announce Type: new Abstract: We characterize bound entanglement in bipartite qutrit systems by combining the Positive Partial Transpose (PPT) criterion with a structural, non-completely positive map. Focusing on a…
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Breaking the Shot-Noise Barrier: Cached Recycled Variance-Reduced Gradients for Quantum Optimization
arXiv quant-ph
arXiv:2609.38800v1 Announce Type: new Abstract: Variational Quantum Algorithms (VQAs) rely heavily on classical optimization routines to navigate high-dimensional, noisy parameter landscapes. However, the evaluation of analytical gradients…
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Reverse quantum state diffusion from differential geometry
arXiv quant-ph
arXiv:2609.39861v1 Announce Type: new Abstract: Quantum state diffusion unravels a Lindblad master equation into stochastic trajectories of pure states. The ensemble of trajectories is described by a probability density on the manifold of…
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Quantum State Routing and Perfect State Transfer on Signed Graphs under Environmental Noise
arXiv quant-ph
arXiv:2609.39890v1 Announce Type: new Abstract: Routing unknown quantum information across distributed communication networks requires autonomous, measurement-free mechanisms to prevent wave-function collapse. Szegedy quantum walks provide…
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Equality in the Bosonic Quantum Entropy Power Inequality
arXiv quant-ph
arXiv:2609.40061v1 Announce Type: new Abstract: The bosonic quantum entropy power inequality bounds the entropy of a beam-splitter output in terms of the input entropies. We determine its complete equality class among independent inputs of…
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Fast Cliffords When Your Quantum Memory Is Full
arXiv quant-ph
arXiv:2609.40144v1 Announce Type: new Abstract: Additional qubits can reduce the depth of a quantum circuit by providing workspace for parallel computation, but standard constructions assume that this workspace is initialized in a known…
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Towards noble gas quantum optical magnetometry using direct ultraviolet detection
arXiv quant-ph
arXiv:2609.38633v1 Announce Type: new Abstract: We analyze a novel approach for quantum magnetic sensing via optical detection of nuclear spin precession in a noble gas. The detection is carried out with an ultraviolet frequency comb…
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Average-and Last-Iterate Lower Bounds for Optimistic Matrix Mirror-Prox in Quantum Zero-Sum Games
arXiv quant-ph
arXiv:2609.38835v1 Announce Type: new Abstract: Optimistic matrix mirror-prox (OMMP) computes $\epsilon$-approximate Nash equilibria in quantum zero-sum games with an $O(1/\varepsilon)$ average-iterate guarantee [arXiv:2311.10859]. We…
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Engineered Dissipation for Thermal-State Tracking Across Quantum Criticality
arXiv quant-ph
arXiv:2609.39084v1 Announce Type: new Abstract: Engineering dissipation has emerged as a powerful strategy for controlling quantum many-body dynamics, complementing purely coherent control for state preparation. However, finite-time…
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Genuine Multipartite Nonlocality Is Fermionic Magic
arXiv quant-ph
arXiv:2609.39411v1 Announce Type: new Abstract: A system of free fermions can be simulated on a classical computer, and a single non-Gaussian state makes it a universal quantum computer. We show that the same line bounds quantum…
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Predicting properties of Scrooge ensembles with high accuracy and low sample complexity
arXiv quant-ph
arXiv:2609.39992v1 Announce Type: new Abstract: The Scrooge ensemble associated with a density matrix $\rho$ is the maximally random ensemble whose average density matrix is $\rho$. It has attracted growing interest for its applications to…
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Bath-assisted cooling without resets
arXiv quant-ph
arXiv:2609.40328v1 Announce Type: new Abstract: Cooling an arbitrary mixed state to a pure ground state requires transferring its entropy to an environment. Can a single coherent bath contact accomplish this without repeated bath resets?…
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Emergence of chaos with exceptional points in reset-driven Floquet dynamics
arXiv quant-ph
arXiv:2605.11751v2 Announce Type: replace Abstract: We investigate the spectral structure of reset-driven Floquet quantum channels generated by the Hamiltonian evolution of a many-body system followed by periodic resetting of a bath. By…
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Resource-Tunable Quantum Circuit Implementation of Nonlinear Element-Wise Transformations
arXiv quant-ph
arXiv:2609.39295v1 Announce Type: new Abstract: Nonlinear transformations are important in quantum machine learning and other quantum numerical applications, which can be reduced to the implementation of element-wise polynomials through…
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Quantum Enhanced Deep Reinforcement Learning for Distribution Network Reconfiguration
arXiv quant-ph
arXiv:2609.40327v1 Announce Type: new Abstract: Modern smart grids generate increasingly rich operational data and deploy greater numbers of remotely controlled switching assets than ever before, creating new opportunities for data-driven…
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Optimal Lower Bound for Ground-State Energy Estimation with a Guiding State
arXiv quant-ph
arXiv:2608.24493v2 Announce Type: replace Abstract: Suppose we can apply the unitary $U=e^{i H}$ for some Hamiltonian $H$, and are given access to a unitary that prepares a guiding state promised to have overlap at least $\gamma >0$ with…
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Stable Long-Range Charging and Boundary-Mediated Thresholds in a Waveguide Quantum Battery
arXiv quant-ph
arXiv:2609.32580v2 Announce Type: replace Abstract: The waveguide-integrated architecture holds promise for scalable on-chip integration of a charger, a transmission channel, and a quantum battery in a modular, independently optimizable…
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CSS codes for Quantum Metrology with Discrete-time Error Correction
arXiv quant-ph
arXiv:2609.40022v1 Announce Type: new Abstract: The goal of quantum metrology is to estimate an unknown parameter with better-than-classical precision and, ideally, to attain Heisenberg scaling. In realistic settings, however, noise can…
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When Symmetry Suppresses Magic
arXiv quant-ph
arXiv:2609.38319v1 Announce Type: new Abstract: Nonstabilizerness is a critical resource for quantum advantage, but evaluating it, especially for mixed states, requires superexponentially many samples in system size, making the problem…
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Exponential strong converse for blind quantum data compression
arXiv quant-ph
arXiv:2609.38328v1 Announce Type: new Abstract: We establish exponential strong converse theorems for blind quantum data compression of finite-dimensional mixed-state sources, with and without entanglement assistance. Blind compression is…
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Collective Dynamics in Spin Chains with Constrained Dissipation: Classically Fragile but Quantum Robust
arXiv quant-ph
arXiv:2609.38333v1 Announce Type: new Abstract: Collective non-equilibrium phenomena in many-body systems are strongly influenced by fluctuations, particularly in the vicinity of phase transitions, where the interplay between classical and…
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Normal-ordered perturbative expansion for matter systems interacting with continuous-mode quantum photon fields
arXiv quant-ph
arXiv:2609.38576v1 Announce Type: new Abstract: We develop a normal-ordered perturbative expansion method to compute the reduced dynamics of a matter system interacting with a general continuous-mode photon field state. In this expansion…
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Classical Algorithms for Function Computation in Gaussian Boson Sampling
arXiv quant-ph
arXiv:2609.38882v1 Announce Type: new Abstract: Gaussian boson sampling (GBS) seeks quantum advantage by sampling photon-number patterns generated with squeezed inputs and passive linear optics. Many proposed GBS applications instead…
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SQD-Agent: LLM-driven agentic framework for Quantum Chemistry workflows
arXiv quant-ph
arXiv:2609.39302v1 Announce Type: new Abstract: Quantum algorithms and quantum hardware are advancing towards a promising paradigm for scientific applications. However, translating domain-specific problems into executable hybrid…
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A Dichotomy for MIP* in the Presence of Unital Noise
arXiv quant-ph
arXiv:2609.39318v1 Announce Type: new Abstract: A recent work studied quantum two-prover one-round proof systems $\mathsf{MIP}^{\psi}[\text{poly},O(1)]$. It showed that when $\psi$ is a noisy EPR state with quantum maximal correlation…
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Quantum Secure Non-Interactive Reductions
arXiv quant-ph
arXiv:2609.38452v1 Announce Type: new Abstract: Efficient models for secure computation often rely on offline preprocessed correlations, which subsequently enable private online computation from minimal assumptions. Within these models…
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Scaling law of variational quantum algorithms
arXiv quant-ph
arXiv:2609.39949v1 Announce Type: new Abstract: We study scaling law of variational quantum algorithms by large-scale numerical experiments on combinatorial optimizations. On experiments up to n = 5000 qubits with O( log(n)) circuit depth…
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Entropy and Variance Squeezing of V-type Atom in Dissipative Cavity
arXiv quant-ph
arXiv:2601.01519v4 Announce Type: replace Abstract: Based on Ref.\cite{Riccardi A}, we investigate the entropy and variance squeezing of a V-type atom in a dissipative cavity, and discuss the influences of parameters including the…
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Quantum Sensing and Hamiltonian Learning under Stochastic Parameter Evolution
arXiv quant-ph
arXiv:2609.39908v1 Announce Type: new Abstract: We introduce the notion of stochastically evolving Hamiltonians (SEHs), which are local Hamiltonians whose coefficients are governed by stochastic differential equations (SDEs). After…
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Many-body topology in parity-preserving tensor networks
arXiv quant-ph
arXiv:2609.40004v1 Announce Type: cross Abstract: Planar parity-preserving tensor networks (ppTNs) admit a fermionic formulation in which the Gaussian, efficiently contractible limit is deformed by local interactions. We investigate how…
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Parallel algebraic surgery for qLDPC codes with constant shuttling depth
arXiv quant-ph
arXiv:2609.39874v1 Announce Type: new Abstract: Reconfigurable atom arrays provide a promising platform for high-rate quantum low-density parity-check codes, but their computational advantage depends on whether logical operations can be…
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Priority-Aware Routing for Quantum Networks:Integrating Coherence-Time Constraints into Scheduling
arXiv quant-ph
arXiv:2609.38380v1 Announce Type: cross Abstract: Quantum networks face a fundamental challenge absent in classical networks; finite memory coherence times mean that queuing delay directly degrades information quality, causing decoherence…
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Bivariate Bicycle Codes and Metachecks: Syndrome Repair, Measurement-Fault Ambiguity, and Logical Obstructions
arXiv quant-ph
arXiv:2609.39121v1 Announce Type: new Abstract: Faulty syndrome measurements can corrupt an otherwise correct quantum-error correction step. Bivariate bicycle (BB) codes contain dependent stabilizer checks, so their measured syndromes obey…
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Optimal Purity Estimation with Incoherent Measurements
arXiv quant-ph
arXiv:2609.40248v1 Announce Type: new Abstract: In this work, we consider the fundamental task of estimating the purity of an unknown state to within $\textit{multiplicative}$ error $\varepsilon$. When one can perform general collective…
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Limit Theorems for Disordered Quantum Trajectories
arXiv quant-ph
arXiv:2609.40096v1 Announce Type: cross Abstract: We study discrete-time quantum trajectories of a finite-dimensional system in a disordered environment, where the instrument applied at each step is determined by an invertible…
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Accessible Quantum Correlations Under Complexity Constraints
arXiv quant-ph
arXiv:2604.15540v2 Announce Type: replace Abstract: Quantum systems may contain underlying correlations which are inaccessible to computationally bounded observers. We capture this distinction through a framework that analyses bipartite…
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Perturbative results for fractional quantum mechanics
arXiv quant-ph
arXiv:2606.03226v3 Announce Type: replace Abstract: The fractional Schr\"odinger equation is studied with a kinetic energy that slightly deviates from the usual nonrelativistic form. The harmonic oscillator and the Kepler problem are both…
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Random unitary circuits with constant spectral gap
arXiv quant-ph
arXiv:2607.20919v2 Announce Type: replace Abstract: We prove constant lower bounds for the spectral gap of the following random walks on unitary groups $\mathsf{SU}(2^n)$ on $n$ qubits. (i) Random Pauli Rotation: choose an $n$-qubit Pauli…
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Dimension-Free Polylogarithmic Quantum Shadow Tomography
arXiv quant-ph
arXiv:2608.06345v3 Announce Type: replace Abstract: Shadow Tomography is a fundamental problem in quantum information theory. Given multiple copies of an unknown $d$-dimensional quantum state $\rho$ and a known collection of observables…
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Bosonic Error Correction with Fluxonium
arXiv quant-ph
arXiv:2609.26880v2 Announce Type: replace Abstract: Bosonic quantum error correction (QEC) offers a hardware-efficient route to fault-tolerant quantum computing. To date, however, superconducting circuit implementations of bosonic codes…
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Semiclassical spin-bath calculation of the nitrogen-isotope effect on NV$^-$ ensemble coherence in diamond
arXiv quant-ph
arXiv:2609.37596v2 Announce Type: replace Abstract: The ratio $T_2$/$T_2^*$ of the Hahn-echo and Ramsey times of nitrogen-vacancy (NV$^-$) ensembles is independent of the nitrogen concentration [N] and is $\approx$ 16 in diamond of natural…
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A Time-Frequency Framework for GKP Codes
arXiv quant-ph
arXiv:2609.10802v3 Announce Type: replace-cross Abstract: We develop a time--frequency framework for lattice GKP codes in which ideal codewords are realized in the modulation space $M^\infty$ and identified, through a vector-valued Zak…
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Making the most of leftovers: Improved privacy amplification for quantum key distribution
arXiv quant-ph
arXiv:2609.38306v1 Announce Type: new Abstract: The amount of secret key that can be obtained from a quantum key distribution run depends on both the physically observed error rates and the mathematical bounds used to certify security. For…
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Experimentally realized local-global tradeoff in quantum resources
arXiv quant-ph
arXiv:2609.40033v1 Announce Type: new Abstract: The interconversion among different quantum resources has attracted considerable attention, exemplified by the tradeoff between coherence and entanglement. However, the relationship between…
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Optical studies of negative g-factor dopants in an antiferromagnet: Nd:GdVO$_4$
arXiv quant-ph
arXiv:2609.38892v1 Announce Type: new Abstract: Neodymium-doped gadolinium vanadate (Nd:GdVO$_4$) is a popular laser material at room temperature. It has received limited attention for quantum technologies because of the linebroadening…
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Complete parameterization and parameter-space topology of discrete Wigner representations on $d \times d$ phase space
arXiv quant-ph
arXiv:2609.39119v1 Announce Type: new Abstract: Toroidal discrete Wigner functions (DWFs) for finite-dimensional systems are non-unique. We classify the labeled single-qudit ${d\times d}$ representations whose phase-point operators are…
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Classical and Quantum Simulation of All-to-All Quantum Dynamics in Logarithmic Space
arXiv quant-ph
arXiv:2609.40162v1 Announce Type: new Abstract: We study both the classical and the quantum complexity of the problem of estimating disorder-averaged quench dynamics for all-to-all spin Hamiltonians such as quantum Hopfield…
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Shadow Quantum Singular Value Transformation with Shallow Quantum Circuits
arXiv quant-ph
arXiv:2609.40167v1 Announce Type: new Abstract: We introduce shadow quantum singular value transformation (Shadow QSVT): given an initial state $|{\psi}\rangle$, a Hermitian matrix $H$, a polynomial $f$, and a set of observables…
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A mixing time method for estimating the sample complexity of quantum state discrimination
arXiv quant-ph
arXiv:2609.40182v1 Announce Type: new Abstract: We develop a mixing time method for estimating the sample complexity of quantum state discrimination. We start with considering the minimum-error discrimination of geometrically uniform pure…
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The Structure of Higher-Order Quantum Resources with an Application to Coherence
arXiv quant-ph
arXiv:2609.40186v1 Announce Type: new Abstract: We develop a general framework for higher-order quantum resources that treats the resourcefulness of quantum states, channels, and supermaps (also called processes) in a unified manner. By…
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Fast classical simulation algorithms for free-fermion dynamics with magic input
arXiv quant-ph
arXiv:2609.40187v1 Announce Type: new Abstract: The classical cost of simulating free-fermion (matchgate) circuits depends on both the input state and the computational task. We develop classical algorithms for circuits with non-Gaussian…
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Query-Limited RAM Programs and their Applications
arXiv quant-ph
arXiv:2609.40194v1 Announce Type: new Abstract: Quantum one-time programs (Broadbent, Gutoski and Stebila, CRYPTO 2013) or OTPs for short, enable a functionality to be encoded into a quantum token that can be evaluated on a single chosen…
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On The Simplest Quantum-Secure Block Cipher
arXiv quant-ph
arXiv:2609.40350v1 Announce Type: new Abstract: Pseudorandom permutations are ubiquitous in theoretical and applied cryptography. PRPs that offer security even against adversaries making quantum queries are of increasing interest, and used…
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An (almost) efficient classical algorithm for sampling from typical Gibbs states
arXiv quant-ph
arXiv:2609.40250v1 Announce Type: new Abstract: Gibbs state preparation has emerged as a potential avenue for quantum advantage in the study of physical systems. Although there is known advantage for computing local properties of…
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Quantum oblique eigenprojection
arXiv quant-ph
arXiv:2609.40254v1 Announce Type: new Abstract: Every square matrix decomposes its underlying Hilbert space into generalized, nonorthogonal eigensubspaces. We show that a quantum computer can perform such an oblique eigenprojection $\Pi$…
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Refined sample complexities from the tomographic rate function
arXiv quant-ph
arXiv:2609.40271v1 Announce Type: new Abstract: Protocols for quantum state tomography can be characterized either by their sample complexity or by the tomographic rate function that governs the large deviation behaviour of error…
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Computational Bounds for $f$-Routing
arXiv quant-ph
arXiv:2609.40278v1 Announce Type: new Abstract: The $f$-routing protocol is a leading candidate for quantum position verification (Kent, Munro, and Spiller, 2011), but security guarantees for explicit functions remain limited. We prove…
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Distinguishing Coherent Crosstalk from Calibration Drift via Pauli-Transfer Signatures and Quantum Edge Detection
arXiv quant-ph
arXiv:2609.40283v1 Announce Type: new Abstract: Multi-tenant quantum processors expose a pulse-level attack surface in which coherent crosstalk can mimic benign calibration drift at matched average gate infidelity. We present a structural…
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Need for Coherent Access in Constructing Quantum Cryptography
arXiv quant-ph
arXiv:2609.40301v1 Announce Type: new Abstract: We construct quantum oracles relative to which quantum-secure one-way functions (OWFs) exist but pseudorandom states (PRSs) with superlogarithmic output length do not. At first glance, this…
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MORE Thermal Gauge Theories at Finite $\theta$ and $\mu$ from Real-Time Quantum Simulation
arXiv quant-ph
arXiv:2609.38569v1 Announce Type: cross Abstract: Imaginary-time evolution can be reconstructed from real-time quantum simulations using exact integral transforms. We identify the construction of Guo, Shibu, Lin, and Zhao as a continuous…
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Relative entropy of entanglement and tripartite minimal surface
arXiv quant-ph
arXiv:2609.38815v1 Announce Type: cross Abstract: We propose a holographic dual of the relative entropy of entanglement for a boundary tripartition $A:B:C$. Our proposal is that, at the leading order, \begin{align} E_R(\rho_{AB}) =…
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Eigenstate thermalization at the edge of the many-body spectrum
arXiv quant-ph
arXiv:2609.38973v1 Announce Type: cross Abstract: It is well-known that thermalization breaks down in presence of an extensive number of symmetries or conservation laws that are mutually compatible or commuting with each other. We ask here…
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Quantum Frozen--Oseen homotopy analysis method with LCHS for solving nonlinear partial differential equations
arXiv quant-ph
arXiv:2609.39170v1 Announce Type: cross Abstract: Nonlinear partial differential equations (PDEs) underpin computational fluid dynamics, yet resolving nonlinear transport on fine grids remains computationally demanding. Quantum…
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No-go theorems for dual Hamiltonians of Non-Abelian Lattice Gauge Theories
arXiv quant-ph
arXiv:2609.39780v1 Announce Type: cross Abstract: Hamiltonian simulations of lattice gauge theories promise new insights into the inner workings of QCD. The rapid development of quantum computing hardware suggests that large scale…
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Exponential Quantum Advantage in Numbers-on-Forehead Communication
arXiv quant-ph
arXiv:2609.40273v1 Announce Type: cross Abstract: We give the first exponential quantum advantage in the general interactive three-party Numbers-on-Forehead (NOF) model for a decision problem. Previous separations hold only for restricted…
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Feedback-Induced Advantage in Quantum Clockworks
arXiv quant-ph
arXiv:2603.04556v2 Announce Type: replace Abstract: Atomic frequency standards have achieved steadily increasing precision over the past seventy years, enabled in part by feedback mechanisms that stabilise their output. In parallel, the…
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Efficiently estimating quantum thermal properties from exponentially fewer samples
arXiv quant-ph
arXiv:2603.16845v2 Announce Type: replace Abstract: We present an efficient protocol for estimating $M$ observables to precision $\varepsilon$ from only $\mathcal{O}(\log (M)/\varepsilon^2)$ copies of a Gibbs state $\rho\propto\exp(-\beta…
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Streaming the partial-transpose moment hierarchy with order-independent quantum memory
arXiv quant-ph
arXiv:2606.14204v3 Announce Type: replace Abstract: Partial transposition reveals mixed-state entanglement through the spectrum of $\rho_{AB}^{T_B}$, but this operator is not generally a physical state. Its power moments are accessible…
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Physical reduced states and continuum characters of the lattice Kramers-Wannier defect
arXiv quant-ph
arXiv:2607.01137v5 Announce Type: replace Abstract: A non-invertible topological line fixes global defect data but does not select a reduced density matrix (RDM) in a spatially twisted sector. For the Kramers-Wannier defect of the critical…
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Full-Trajectory Learning of Open Quantum Systems: Dynamical Emulation and the Limits of Hamiltonian Identifiability
arXiv quant-ph
arXiv:2608.23025v2 Announce Type: replace Abstract: Accurate identification of unknown quantum systems is essential for quantum computing, sensing, and control because the Hamiltonian governs quantum state evolution. This work proposes a…
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Quantum Fourier transform toolbox
arXiv quant-ph
arXiv:2608.28573v2 Announce Type: replace Abstract: Quantum Fourier transforms (QFTs) are essential primitives in quantum algorithms. While abelian groups admit efficient QFT circuits, with circuit size polynomial in the logarithm of the…
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Casimir force in a water nanolayer confined by graphene sheets
arXiv quant-ph
arXiv:2609.23609v2 Announce Type: replace Abstract: Casimir forces, arising from quantum and thermal fluctuations, depend strongly on the electromagnetic susceptibilities of the interacting materials. Here, we theoretically investigate the…
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Learning quantum symmetries
arXiv quant-ph
arXiv:2609.38085v2 Announce Type: replace Abstract: Quantum algorithms are powerful tools for finding symmetries of classical objects, most famously through Shor's algorithm and the Hidden Subgroup Problem (HSP). In this work, we study…
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Information Thermodynamics of Agents: The Work Capacity of Channels with Memory
arXiv quant-ph
arXiv:2504.06209v2 Announce Type: replace-cross Abstract: Predicting future observations plays a central role in machine learning, biology, economics, and many other fields. It lies at the heart of organizational principles such as the…
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The Generalized Semi-Clifford Conjecture Holds at Level 4
arXiv quant-ph
arXiv:2609.38751v1 Announce Type: new Abstract: The Clifford hierarchy $\mathsf{C}_1 \subset \mathsf{C}_2 \subset \cdots$ was introduced by Gottesman and Chuang (arXiv:quant-ph/9908010) to characterize gates that admit fault-tolerant…
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Boundary-rank obstructions and measurement-assisted recovery in dissipative flat-band preparation
arXiv quant-ph
arXiv:2609.38933v1 Announce Type: new Abstract: Number-conserving cooling can fail to prepare an interacting flat-band target when Pauli exclusion blocks its transfer destinations. We study this failure on vertex-edge decorated graphs at…
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Defect-Aware Parallel Atom Reloading Protocol for Neutral-Atom Quantum Computers
arXiv quant-ph
arXiv:2609.38939v1 Announce Type: new Abstract: In this work, we propose a defect-aware parallel atom reloading protocol that reloads atoms based on defect information to increase the atom filling rate. The proposed protocol is useful for…
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Spectrally Selective Charging of an Interacting Quantum Battery via an Anharmonic Mediator
arXiv quant-ph
arXiv:2609.39393v1 Announce Type: new Abstract: We investigate a finite-time quantum-battery charging architecture in which a driven two-level working system transfers nonequilibrium resources to an interacting two-qubit battery through a…
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Transducer-based linear combination of unitaries: theory and applications
arXiv quant-ph
arXiv:2609.40073v1 Announce Type: new Abstract: Linear combination of unitaries (LCU) is a fundamental primitive in quantum algorithms, whose cost is typically governed by the most expensive unitary appearing in the combination. We develop…
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A Complete and Natural Rule Set for Multi-Qudit Clifford Circuits in All Odd Prime Dimensions
arXiv quant-ph
arXiv:2609.40106v1 Announce Type: new Abstract: We present a complete set of $16$ rewrite rules for multi-qudit Clifford circuits in all odd prime dimensions. Completeness means that any two Clifford circuits representing the same linear…
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Local Relaxation Hierarchies for Quantum Ground State Energies: Convergence Guarantees and Message Passing Algorithms
arXiv quant-ph
arXiv:2609.40336v1 Announce Type: new Abstract: Convex relaxation hierarchies provide lower bounds to the ground state energy of quantum many-body systems that can be computed in polynomial time on a classical computer, at any fixed…
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Square-root growth of operator entanglement in an integrable brickwork circuit
arXiv quant-ph
arXiv:2609.39401v1 Announce Type: cross Abstract: It is widely expected that the von Neumann entanglement of a local operator grows at most logarithmically in integrable many-body systems in infinite volume. We give a counterexample in a…
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High-threshold magic state distillation with quantum quadratic residue codes
arXiv quant-ph
arXiv:2603.18560v2 Announce Type: replace Abstract: We present applications of quantum quadratic residue codes in magic state distillation. This includes showing that existing codes which are known to distill magic states, like the…
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Surprisingly High Redundancy in Electronic Structure Data Across Materials Explained by Low Intrinsic Dimensionality
arXiv quant-ph
arXiv:2507.09001v4 Announce Type: replace-cross Abstract: Machine learning (ML) models for electronic structure typically rely on large datasets generated by computationally expensive Kohn-Sham density functional theory calculations, as it…
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Full Eigenstate Thermalization in Integrable Spin Systems
arXiv quant-ph
arXiv:2510.05887v3 Announce Type: replace-cross Abstract: The Eigenstate Thermalization Hypothesis (ETH) is a standard tool to understand the thermalization properties of an isolated quantum system. Its generalization to higher order…
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Q-SPARSE: Quantum Subspace Projection for Near-Field Angle-Range Spectrum Estimation
arXiv quant-ph
arXiv:2609.38500v1 Announce Type: new Abstract: Near-field wavefront curvature enables joint angle-range localization, but exploiting it entails repeated covariance-eigenspace tests over a two-dimensional spherical manifold. We propose a…
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Information Potential: A Variational Approach to Quantum Information Complexity
arXiv quant-ph
arXiv:2609.39328v1 Announce Type: new Abstract: Quantum information complexity (QIC), introduced by Touchette [Touchette, STOC 2015], has been shown to be one of the most powerful methods for proving quantum communication complexity and…
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Dynamic distributed quantum sensing of radio-frequency fields via time-bin entanglement
arXiv quant-ph
arXiv:2609.39831v1 Announce Type: new Abstract: We propose a novel framework for discrete-variable (DV) distributed quantum sensing, wherein traditional polarization-based probes are replaced with time-bin entangled qubits. We show that…
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Single-shot state preparation threshold: rigorous theorem and statistical mechanical mapping
arXiv quant-ph
arXiv:2609.39965v1 Announce Type: new Abstract: Preparing logical codewords with a single round of noisy syndrome measurements can reduce the time overhead of fault-tolerant quantum computation. It remains unclear which structural…
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Measurement-induced dynamics and emergent symmetries of particles moving in a one-dimensional lattice
arXiv quant-ph
arXiv:2609.40026v1 Announce Type: new Abstract: Continuous measurements simultaneously reveal and modify the dynamics of a quantum system. In this work we consider the tunneling motion of particles between the sites of a one-dimensional…
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Reducing the Entanglement Cost of Distributed Bipartite Quantum Computation with Constant Qubit Overhead
arXiv quant-ph
arXiv:2609.39865v1 Announce Type: new Abstract: Distributed quantum computation connects multiple quantum processing units (QPUs) through quantum communication to jointly perform large-scale quantum computations. Since the number of qubits…
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Haah's 3D cubic code thermalizes rapidly
arXiv quant-ph
arXiv:2609.39959v1 Announce Type: new Abstract: Haah's 3D cubic code was introduced as a candidate for a self-correcting quantum memory in three dimensions, using the absence of string logical operators to obstruct thermal errors. It has…
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Characterization of Josephson Junction Aging and Annealing Under Different Environments
arXiv quant-ph
arXiv:2602.23888v3 Announce Type: replace Abstract: Understanding the aging behavior of Josephson junctions and the effect of annealing on junction resistances is important in building large-scale superconducting quantum processors. Here…
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A Few Constrain Many: Correlation-Enhanced Learning of Many-Body Quantum Systems
arXiv quant-ph
arXiv:2609.39935v1 Announce Type: new Abstract: Discovering properties of many-body quantum systems is challenging because of the large number of parameters to determine. Here, we show that correlations among quantum observables help…
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A self-tallying quantum anonymous voting protocol for multiple-selection elections
arXiv quant-ph
arXiv:2609.39835v1 Announce Type: new Abstract: Self-tallying quantum anonymous voting (SQAV) has drawn considerable attention since it was proposed. However, constrained by design challenges, all existing protocols only accommodate…
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All Unitaries Have Constant Depth Quantum Circuits
arXiv quant-ph
arXiv:2609.40351v1 Announce Type: new Abstract: It is well-known that every $n$-qubit unitary can be implemented by a $2^{O(n)}$-depth quantum circuit using single- and two-qubit gates. It has been open whether exponential depth is…
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From Random Quantum Codes to Explicit qLDPC Codes via Local Properties
arXiv quant-ph
arXiv:2609.40252v1 Announce Type: cross Abstract: Constructing explicit codes matching the parameters of random codes has been a central and largely elusive question in coding theory. The quantum setting is even more challenging since it…
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The twisted convolution identity and ghost $r$-SICs from finite quantum dilogarithms
arXiv quant-ph
arXiv:2609.39192v1 Announce Type: cross Abstract: Radchenko and Wheeler (RW) recently proved a finite pentagon relation for real quadratic special values of the modular quantum dilogarithm and used it to establish the rank-$1$ twisted…
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Causal-Order Identification of Memoryless Sequential Quantum Processes from Restricted Projective Data
arXiv quant-ph
arXiv:2605.04571v4 Announce Type: replace Abstract: Identifying causal order from restricted projective data is generally nontrivial. When two quantum players interact only through an unobserved environment, the available local measurement…
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The Moreau-Yosida approximation of the Entanglement of Formation: basic properties and accuracy estimates
arXiv quant-ph
arXiv:2609.30246v2 Announce Type: replace Abstract: We describe a family of convex uniformly continuous functions $E^\lambda_F$, $\lambda>0$, on the set of states of a bipartite quantum system (consisting of finite-dimensional or…
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Probing quantum Hall edge chirality and the anyonic exchange angle with a three-path interferometer
arXiv quant-ph
arXiv:2607.24451v2 Announce Type: replace-cross Abstract: An upstream neutral mode can influence quasiparticle tunneling even when electric charge propagates only downstream. We propose a three-path fractional quantum Hall interferometer…
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Quantum--classical break-even in electronic dynamics of macrocyclic molecules
arXiv quant-ph
arXiv:2609.39693v1 Announce Type: new Abstract: Here we demonstrate quantum--classical break-even for chemical dynamics applications, reaching useful accuracy with a quantum-hardware wall-clock time comparable to that estimated for…
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Distillation of N-Qubit Stabilizer States on a Star Network Topology
arXiv quant-ph
arXiv:2609.39916v1 Announce Type: new Abstract: We introduce an entanglement distillation protocol that utilizes an arbitrary $[[n,k,d]]$ stabilizer code to convert $n$ raw copies of an $N$-qubit Greenberger-Horne-Zeilinger (GHZ) state…
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Fault-tolerant cost of shallow QAOA on near-symmetric optimization problems
arXiv quant-ph
arXiv:2609.39922v1 Announce Type: new Abstract: Montanaro and Zhou proved that depth-one Quantum Approximate Optimization Algorithm (QAOA) finds the planted solution of certain near-symmetric constraint satisfaction problems with…
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Quantum List Recovery and Decoding: Achievability and Limitations
arXiv quant-ph
arXiv:2609.40262v1 Announce Type: new Abstract: Quantum list recovery (QLR) and quantum list decoding (QLD) seek short lists of logically distinct Pauli corrections consistent with a syndrome and prescribed error constraints. For CSS…
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Single-particle detection of the N\'eel transition in LaCrO$_3$ microcrystals via widefield nitrogen-vacancy center magnetic imaging
arXiv quant-ph
arXiv:2609.38529v1 Announce Type: cross Abstract: Rare-earth orthochromites exhibit rich, chemically tunable magnetic behavior, making them attractive for temperature sensing and temperature-dependent switching applications. Realizing this…
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EPR Count for Runtime Prediction in Distributed Quantum Computing
arXiv quant-ph
arXiv:2609.39851v1 Announce Type: cross Abstract: EPR-pair consumption is commonly used as a communication-cost objective in distributed quantum computing, but minimizing EPR cost does not necessarily minimize distributed execution time…
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Optimal and improved gate decompositions for accelerated classical simulation of near-Gaussian fermionic circuits
arXiv quant-ph
arXiv:2603.18869v2 Announce Type: replace Abstract: Fermionic Gaussian circuits can be simulated efficiently on a classical computer, but become universal when supplemented with non-Gaussian operations. Similar to stabilizer circuits…
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Quantum metrology via partial quantum error correction
arXiv quant-ph
arXiv:2605.08341v3 Announce Type: replace Abstract: We introduce a quantum metrology scheme in which partial quantum error correction suppresses local noise while preserving sensitivity beyond the standard quantum limit. The probes are…
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Optimal Fusion Strategies for Quantum Computation
arXiv quant-ph
arXiv:2609.02559v2 Announce Type: replace Abstract: Logical fusions are important for a number of tasks in quantum information, such as quantum error correction and quantum repeaters. In the photonic setting one must contend with the fact…
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Non-abelian quantum cellular automata: $1{+}1$-dimensional $SU(2)$ Yang--Mills with fermions
arXiv quant-ph
arXiv:2609.30285v2 Announce Type: replace Abstract: This work provides a digital quantum simulation scheme for $1{+}1$-dimensional $SU(2)$ Yang--Mills theory with Dirac fermions. It takes the form of a quantum circuit, infinitely repeating…
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A Separation Between Types of Quantum Oracle Separations
arXiv quant-ph
arXiv:2609.38704v1 Announce Type: new Abstract: Recent works have demonstrated that quantum oracles have subtle behavior, as access to inverse, conjugate or controlled queries can exponentially change the query complexity of certain tasks…
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Optical measurement is almost quantum: Quantum inspired universal optical bounds
arXiv quant-ph
arXiv:2609.39857v1 Announce Type: new Abstract: Inspired by results in quantum information, we report the development of a formalism for optical sensing which abstracts the details of specific optical systems and allows us to form general…